The Mississippi Chapter of the American College of Physicians sent Bryant a letter Friday that read: “No matter where one stands on the Affordable Care Act itself, the evidence is clear: Mississippi will greatly benefit by accepting federal dollars to extend Medicaid, and Mississippians will be harmed if it does not.”

The group has 569 members who practice internal medicine or subspecialties. It also has 351 medical students as members.

The Mississippi Academy of Family Physicians already has endorsed Medicaid expansion, as have several hospital administrators.

The Mississippi Chapter of the American Academy of Pediatrics has not taken a formal position on the Medicaid issue. However, the group has surveyed its members, and “a large majority of our members do favor expansion,” Dr. Tami Brooks of Jackson, the group’s legislative director, said Friday.

“It would be another means to provide universal access” to medical care, Brooks said.

Bryant spokesman Mick Bullock the state can’t afford for one-third of its residents to enroll in the government insurance program. About one-fifth of residents are already enrolled.

“Any expansion of Medicaid would result in tax increases for Mississippians or cuts to critical spending in areas like education, public safety and economic development,” Bullock said Friday.

Under the federal health overhaul that President Barack Obama signed in 2010, states have the option of expanding Medicaid to people making up to 138 percent of the federal poverty level, or about $15,000 for an individual. Mississippi’s current cutoff is about $5,500, and the state’s program doesn’t cover many able-bodied adults.

Mississippi is one of the poorest states in the nation with one of the highest percentages of uninsured residents. About 530,000 residents younger than 65 are uninsured, according to a study the Urban Institute conducted for the nonpartisan Kaiser Family Foundation. That’s 21 percent of the state’s nonelderly residents.

In a population of roughly 3 million, more than 640,000 are already on Medicaid, and expansion could add as many as 300,000.

Leaders of the Republican-led state House and Senate also have said the state can’t afford expansion, while many Democrats say the state can’t afford to reject federal money that could support an estimated 9,000 health care jobs.

Sen. Hob Bryan, D-Amory, led a Public Health subcommittee meeting on Tuesday, focusing on how broadening the program could help cover people who work full time in low-paying jobs that don’t provide private insurance.

The 2010 law says the federal government would pay 100 percent of medical expenses for the newly qualified enrollees from 2014 to 2017. The federal share would be reduced to 90 percent by 2020, with each state paying the balance.

Dr. Robert Brahan of Hattiesburg, leader of the Mississippi Chapter of the American College of Physicians, said expanding Medicaid would be one step toward improving access to health care. He said he wants the House and Senate to debate the issue before the three-month legislative session ends in early April.

“I think there needs to be an open discussion about it,” Brahan said Friday.

Brahan said the state also has about half the number of physicians it needs, and educating new ones will take years.

During the State of the State speech in January, Bryant called on lawmakers to fund a new medical school building at the University of Mississippi Medical Center. The governor said with the expanded school, UMMC could train 1,000 new physicians by 2025.